Is There a Difference Between Tiffany, Costco Diamonds?

Oct. 9, 2005 — -- Diamonds are a $30 billion a year business. You can buy a diamond at the mall, at a fancy boutique and even online. With so many merchants selling them, how can you be sure you're getting a good stone at a fair price?

"Good Morning America" shopped at both ends of the spectrum, buying one diamond ring at Tiffany & Co. for $16,600 and one at Costco for $6,600.

All diamonds come from deep within the Earth, but there are lots of different places you can go to get one. We started at Tiffany. We had thousands of diamonds and elaborate settings to choose from, starting at $1,200.

Tiffany has a unique policy that allows you to exchange a modest ring for something fancier years later. Tiffany will also clean your diamond and make sure the setting is secure for the rest of your life.

The 168-year-old retailer is famous for educating its customers about diamonds, carefully explaining about the "4 Cs," which are carat weight, cut, color and clarity. The staff will even take you into a private room to examine different stones under a high-powered microscope.

After visiting the store everybody thinks of for diamonds, we went to the store that next to nobody thinks of for diamonds -- Costco.

At the Costco store "GMA" visited, the employee who manages the jewelry department is also in charge of things like big screen TVs and computers.

There were 25 diamond rings to choose from, ranging in price from $500 to $23,000. There's more variety on the Costco Web site, and you can always buy a diamond ring at the store and have it re-set somewhere else.

"We are not really a jewelry store, so we don't carry the best of the best, but we do try to carry top quality," said Juan, the sales clerk who was helping us.

So, the Costco experience was less romantic. But what about the diamonds themselves? Martin Fuller, considered one of the finest master gemologists and appraisers on the East Coast, carefully analyzed our purchases.